Pressure switch



Feb. 22, 1966 E. A. PARMANN ETAL 3,236,963

PRESSURE SWITCH Filed Jan. 16, 1964 2 Sheets-Sheet 1 Feb- 22, 1966 E. A.PARMANN ETAL 3,235,953

PRESSURE SWITCH Filed Jan. 16, 1964 2 Sheets-Sheet 2 United StatesPatent O 3,236,963 PRESSURE SWITCH Edwin A. Parmann, Batavia, and .lohnFirth Marquis, St. Charles, Iii., assignors to Fnrnas Electric Company,Batavia, Ill., a corporation of Delaware Filed Jan. 16, 1964, Ser. No.338,153 4 Claims. (Cl. 200-67) The invention relates to electricswitches and has reference more particularly to pressure actuatedswitches of the toggle type for controlling and protecting electricmotors when providing power for water pumps, air compressors and thelike.

An object of the invention is to provide a toggle actuated pressureswitch which will be simple in construction, embodying relatively fewparts, which will be highly efficient in operation and which can bereadily adjusted for contact closing at different pressure settings andalso adjustable for varying the spread between the cut-in and cut-outpressures.

Another object of the invention is to provide a pressure switch of thetoggle actuated type which will incorporate a lost motion connectionbetween the snap acting toggle member and the contact strips to enablethe toggle member to gain some momentum in an opening direction beforethe contact strips are engaged, whereby the initial opening action ofthe contact strips is fast enough to prevent arcing.

Another and more specific object of the invention resides in theprovision of a connecting bar of insulating material which is disposedtransversely for joining the spaced contact strips of the toggle switchmechanism and wherein a lost motion connection is provided between thetoggle member and the said insulating bar.

Another object is to provide a pressure actuated lever for actuating thetoggle mechanism and which will have a pivotal connecton with the bottomwall of the frame structure housing the switch mechanism.

With these and various other objects in view, the invention may consistof certain novel features of construction and operation, as will be morefully described and particularly pointed out in the specication,drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the device and whereinlike reference characters are used to designate like parts.

FIGURE l is a longitudinal sectional View, taken vertically through thepressure switch of the invention substantially along line 1 1 of FIGURE2, and showing the toggle mechanism in a closed contact position;

FIGURE 2 is a top plan view of the switch of FIGURE 1 takensubstantially along line 2 2 of FIGURE 1;

FIGURE 3 is an end elevational view looking at the right hand end oFIGURE 1;

FIGURE 4 is a bottom plan View substantially along line 4 4 of FIGURE 1showing the toggle mechanism, and also the connecting bar of insulatingmaterial and the contact strips associated therewith;

FIGURE 5 is an end elevational View looking at the left hand end ofFIGURE 1;

FIGURE 6 is a longitudinal sectional view similar to FIGURE 1, takenvertically through the switch but showing the toggle mechanism in anopen position as regards the contacts;

FIGURE 7 is a detail sectional view taken substantially along line 7 7of FIGURE 2 and showing the contact strip in circuit closed position;

FIGURE 8 is a detail sectional view similar to FIG- URE 7 but showingthe contact strip in circuit open position; and

FIGURE 9 is an enlarged fragmentary sectional View showing the bracketand hinge structure for the toggle 3,236,963 Patented Felo. 22, 1965member and for the toggle actuating lever, with the parts beingpositioned as shown in FIGURE 6.

The supporting frame and housing cover for the switch of the inventionare respectively indicated by numerals 10 and 11, and as best shown inFIGURES l, 2 and 3 the supporting frame 10 includes a bottom wall 12 andupstanding side walls 13 and 1d. The housing cover 11 is removable as aunit from the frame to expose the switch, which essentially includes thecontact block 15 and the pressure actuated lever 16. Projections 17 areformed on the contact block and said projections iit within openings 18in the side walls 13 and 14 for releasably retaining the contact blockin place.

The nozzle 20 is suitably secured to the nozzle ange 22 and theresilient rubber diaphragm 21 is interposed between and sealed by thebottom wall and by the nozzle flange 22. The nozzle proper is internallythreaded at 23 for securement to a source of pressure which actuates thediaphragm 21 and which in turn actuates the pressure lever 16. The saidlever is pivoted at Z4, FIG- URE 1, to the bottom wall 12 andintermediate its length the lever has a depressed portion 25 which liesdirectly over and has contact with the diaphragm 21. The free end oflever 16 is held by the power spring 26 which encircles the power springscrew 27, the head of the screw being located below the bottom wall 12and eX- tending through an opening therein to within the power spring26. The power spring 26 is thus coniined between the lever and thecompression adjusting member 23 which is threaded at the upper end ofthe screw 27. By adjusting the position of member 23 on screw 27 thecompression force of the power spring 26 can be varied and thus theswitch mechanism can be adjusted to cut-out at different pressures.

The contact block 1.5 of insulating material carries the metal terminals3i) and 31, FIGURES 2, 3 and 5, for the conductors to the line andsimilar terminals 32 and 33 are provided at the opposite end of thecontact block for the motor line conductors. The terminals are bentaround the respective ends of the block and the terminals are positionedbetween the center rib 34 and the side ilanges 35 for terminals 3G and32, and between the center rib 34 and the side anges 36 for theterminals 31. and 33. A terminal screw such as 37 is provided for eachterminal for fastening the conductors to the said elements. Theterminals 3@ and 31 have the iixed contacts 33 and di) suitably securedto their underside as shown in FIGURE 3. The terminals 32 and 33 havethe copper contact strips 41 and 4t2; riveted at 39 to their undersideand the said contact strips extend longitudinally so as to overlie theXed contacts on the terminals 3i) and 31, respectively. At this end ofthe contact strips the same are provided with the contacts 43 and d4,which, of course, have movement, due to the flexing of the contactstrips, for coaction with the iiXed contacts 38 and 40.

FIGURES 7 and 8 clearly show the manner in which the terminals 3i), 31,32 and 33 are bent around the respective ends of the contact block 15.Said iigures also show the contact strips such as 41 and the manner inwhich lthe contact strips ileX for opening and closing the contacts ofthe present switch mechanism.

In accordance with the invention the contact strips 41 and d2 areconnected 4by the bar 45 of insulating material, the said bar beingriveted at 45 to each of the strips. The inherent resiliency of thecontact strips is such as to maintain the movable contacts 43 and 44 inengagement with the fixed contacts 38 and 40, respectively. Accordingly,in order to separate the contacts and disconnect the motor conductorsfrom the power line, it is necessary to move the flexible contact stripsin a downward direction. This is accomplished by means of a togglemember adapted to have snap action and which has a lost motionconnection with the bar 45, all in a manner which will now be described.

The numeral 43 yindicates the toggle member which has -a pivotalintergaging connection at Sti with the bracket 51, FIGURE 9, the bracketbeing fixed to `the depending part 52 provided by the contact block 15.The toggle member 48 is characterized by an arm 53 located approximatelycentrally of the member and which depends below the same and projectsto` the left as shown in FIGURES 9 and 6. The bar 45 is located betweenthe arm and the toggle member, and it will be noted that the spaceoccupied by the bar is greater than the thickness of the bar. Thisprovides a lost motion connection between the parts.

The toggle actuating lever 54, FIGURES 1, 6 and 9, also has a pivotalconnection at 55 with the bracket 51 and which is located onapproximately the same axis as that of the toggle member 4S. An openingis provided approximately centrally of the length of the lever 54 forreceiving the bulbous nose of the pin 56. rThe base end of the pin isreduced in diameter and said reduced end is received in an opening inthe pressure lever 16. Thus the pin operatively connects the pressurelever with the toggle actuating lever. Upward movement of the lever 16will produce similar upward movement of the toggle actuating lever 54.However, said upward movement of the lever 54 will take place againstthe compressive force of the coil spring 57, which is contined betweenthe top wall of the contact block and the toggle actuating lever 54 atits connection with the pin 56.

The toggle mechanism is completed by the over-center spring 58 and whichis formed of resilient material having the shape of the letter C toprovide the desired snap action for the elements of the toggle. Theover-center spring 5S has a pivotal interconnecting engagement at 60with the outer free end of the toggle actuating lever 54 and saidover-center spring has a similar pivotal connection at 61 With the outerfree end of the `toggle member 48. The toggle elements normally assumethe position shown in FIGURE l where the actuating lever 54 slantsdownwardly and thus the over-center spring 55 yieldingly biases thetoggle member 48 into its upward position where the outer free end ofthe member engages .the top wall of the contact block. With the togglemember so located in its upward position, the bar 45 connecting thecontact strips 41 and 42 is engaged by the arm 53 and the contacts ofthe switch are caused to close -as shown in FIGURE 7. This position ofthe parts occurs when the pressure force acting on the undersurface ofthe diaphragm 21 is below that of the compression exerted by the coilspring 26 and coil spring 62 on the pressure lever 16. r1`he action ofthe .arm 53 is such as to press on the bar 45 to hold the contacts in aclosed circuit position.

When the pressure of the gas, water, or other liquids on the diaphragm21 exceeds the hold down force of the coil spring 26 and coil spring 62,the lever 16 and the lever 54 are 4caused to pivot upwardly and lat apredetermined pressure level, or in other words, at approximately ahorizontal positioning of the toggle actuating lever 54, the over-centerspring 58 will produce a snap movement of the toggle member 48 into itsdown position as shown in FIGURE 6. In said `down posit-ion of thetoggle member the free end of the member engages a bottom wall of thecontact block. The effect of this pivotal movement of the toggle memberin a downward `direction is to cause the bar 45 to also move down andthus the contact strips are actuated to open the contacts of the switchas shown in FIGURE 8.

The lost motion connection between the toggle member and the connectingbar allows the opening action of the toggle member to gain some momentumbefore the bar is engaged and moved to open the contacts. As a resultthe initial opening action of the contacts is fast enough to preventarcing.

That portion of the contact block indicated by numeral 52 is cored toprovide a bore or receiving the diierential spring 62, FIGURES 1 and 6.The differential pin 63 has contact with the lower end of the spring.and the compressive force of the spring can be adjusted by the threadedcap screw 64. The pin 63 has contact with the pressure lever 16 and thusthe differential spring 62, and also the main spring 26 will force thelever down against the pressure of the gas or liquid on the underside ofthe diaphragm 21. The switch contacts are caused to open only when thepressures on the lever 16 reach a predetermined level suicient toelevate the lever the required amount against the compressive force ofboth springs 26 and 62. This is known as the cut-out pressure of theswitch. By adjustment of the cap screw 64 the difference or spreadbetween the cut-out pressure and the cut-in pressure for the presentswitch mechanism can be adjusted. Compressing the differential spring 62affects both cut-out pressure and dilierential range of the switch.However, increased pressure on the differential spring 62 does notaffect the cut-in operation of the switch.

The invention is not to be limited to or by details of construction ofthe particular embodiment thereof illustrated by the drawings, asvarious other forms of the device will, of course, be Vapparent to thoseskilled in the art without departing from the spirit of the invention orthe scope of the claims.

What is claimed is:

1. In an electric switch of the toggle type, a contact` block of`insulating material having a pair of spaced terminal members at eachend, the pair of terminal members at one end of the block each having afixed contact, a metal contact strip secured to each spaced terminalmember at the other end of the block and said contact strips extendinglongitudinally so as to overlie the fixed contacts respectively, amovable contact secured to each contact strip and adapted to haveclosing and opening action with its respective fixed contact, a contactbar of insulating material extending transversely of the contact blockand being xed at each end to a contact strip, a toggle device foreffecting movement of the contact bar for said closing and openingaction of the movable contacts, said toggle device including a toggleactuating lever and a toggle member having an arm integral therewith andwhich provides a slot for receiving the contact bar, an overcenterspring disposed between and connecting the toggle actuating lever andthe toggle member, a bracket carried by the contact block and providinga support on which the toggle actuating lever and the toggle member arepivotally mounted, and the said slot which receives the contact barproviding an opening of greater depth than the thickness of the bar toform a lost motion connection between the bar and the toggle member inboth directions of movement of the member.

2. An electric switch of the toggle type as defined b claim 1, whereinthe toggle actuating lever and the toggle member .are mounted on saidsupport for pivotal movement on approximately the same transverse axis.

3. In an electric switch of the toggle type, `a frame providing a bottomwall, a .pressure actuated lever pivotally mounted at one end in thebottom wall, a power spring lin compression against the other end of thelever for yieldingly maintaining the lever in contact with the bottomWall, `a contact block carried by the frame above the lever, a toggledevice carried by the contact block on the underside thereof adjacentthe lever, said toggle device including a toggle actuating leverpivotally supported at one end, a toggle member also pivotally supportedat one end on approximately the same axis as the toggle actuating lever,an overcenter spring connecting the ends of the lever and memberopposite their pivot ends, and a pin located between the toggleactuating lever `and the free end of the pressure actuated lever forpositively transmitting movement of the pressure actuated lever in acontact opening direction to the toggle actuating lever.

4. In an electric switch of the .toggle type, a frame providing a bottomwall, a pressure actuated lever pivotably mounted at one end in thebottom wall, a power spring in compression against the other end of thelever, a cont-act block carried by the frame above `the lever, a toggledevice provided by the contact block and located on the underside of`the block, said toggle device including a toggle actuating leverpivotally supported at one end, a toggle member also pivotally supportedat one end on :approximately -the same axis as the toggle actuatinglever, an overcenter spring connecting .the lever and member oppositetheir pivot ends, a pin located between and havling Contact with thepressure actuated lever and the toggle actuating lever for positively.transmitting upward movement of the pressure `actuated lever to 4t-hetoggle actuating lever, la diierential spring carried and positioned bythe contact block, means extending between the diiferential spring andthe pressure actuated lever for transmitting the compressive force ofsaid spring to the lever, `and means for adjusting the compressive forceexerted by the spring.

References Cited by the Examiner UNITED STATES PATENTS 2,439,747 4/ 1948Nelson 200-67 2,771,527 11/ 1956 Hausler 200-166 3,046,368 7/1962Kaminky 200-83 References Cited hv the Applicant UNITED STATES PATENTS2,773,144 12/1956 Immel et al. 2,782,277 2/ 1957 Immel. 2,892,050 6/1959 Fisher. 2,919,321 12/1959 Lung.

BERNARD A. GILHEANY, Primary Examiner. R. K. SHAEFER, Examinez'.

G, MAIER, Assistant Examiner.

1. IN AN ELECTRIC SWITCH OF THE TOGGLE TYPE, A CONTACT BLOCK OFINSULATING MATERIAL HAVING A PAIR OF SPACED TERMINAL MEMBERS AT EACHEND, THE PAIR OF TERMINAL MEMBERS AT ONE END OF THE BLOCK EACH HAVING AFIXED CONTACT, A METAL CONTACT STRIP SECURED TO EACH SPACED TERMINALMEMBER AT THE OTHER END OF THE BLOCK AND SAID CONTACT STRIPS EXTENDINGLONGITUDINALLY SO AS TO OVERLIE THE FIXED CONTACTS RESPECTIVELY, AMOVABLE CONTACT SECURED TO EACH CONTACT STRIP AND ADAPTED TO HAVECLOSING AND OPENING ACTION WITH ITS RESPECTIVE FIXED CONTACT, A CONTACTBAR OF INSULATING MATERIAL EXTENDING TRANSVERSELY OF THE CONTACT BLOCKAND BEING FIXED AT EACH END TO A CONTACT STRIP, A TOGGLE DEVICE FOREFFECTING MOVEMENT OF THE CONTACT BAR FOR SAID CLOSING AND OPENINGACTION OF THE MOVABLE CONTACTS, SAID TOGGLE DEVICE INCLUDING A TOGGLEACTUATING LEVER AND A TOGGLE MEMBER HAVING AN ARM INTEGRAL THEREWITH ANDWHICH PROVIDES A SLOT FOR RECEIVING THE CONTACT BAR, AN OVERCENTERSPRING DISPOSED BETWEEN AND CONNECTING THE TOGGLE ACTUATING LEVER ANDTHE TOGGLE MEMBER, A BRACKET CARRIED BY THE CONTACT BLOCK AND PROVIDINGA SUPPORT ON WHICH THE TOGGLE ACTUATING LEVER AND THE TOGGLE MEMBER AREPIVOTALLY MOUNTED, AND THE SAID SLOT WHICH RECEIVES THE CONTACT BARPROVIDING AN OPENING OF GREATER DEPTH THAN THE THICKNESS OF THE BAR TOFORM A LOST MOTION CONNECTION BETWEEN THE BAR AND THE TOGGLE MEMBER INBOTH DIRECTIONS OF MOVEMENT OF THE MEMBER.